Drying oven



June 22, 1943. F. s. BAILEY Erm.

DRYING OVEN Filed June 28, 1941 4 Sheets-Sheet 1 uw n ww k MNN f 't f V Qt l INVENToRs fire-@seran 5. 5412s,' HaaL Salva/vs ATTORNEY June 22, 1943. F. s. BAILEY Erm. 2,322,272

DRYING OVEN Filed June 28, 1941 4 Sheets-Sheet 2 ATTORNEY June 22, 1943. F. s. BAILEY nm. 2,322,272

DRYING OVEN Filed June 28, 1941 4 Sheets-Sheet 3 gym INVENToRs 4 Sheets-Sheet 4 INVENToRs PAM/2 .Skv/wv i I il' ATORNEY @fain/ar .5'. 5612er F. S. BAILEY ETAL DRYING OVEN Fild June 28. 1941 June 222, 1943.

Patented .lune 22, 1943 name ov'EN Frederick S. Bailey. Hoboken. and Paul Schone,

Ridgeeld, N. J., assignors to National-Standard Company, a corporation of Michigan Application June 28, 1941, Serial No. 400,240

2 Claims.

This invention relates to ovens or heating devices for use in drying lacquered or varnished metal plates or other articles. As is well known, ovens of this character usually consist of an elongated chamber through which an endless conveyor carries the varnished plates. The conveyor usually consists of several chains carrying a plurality of racks for supporting the plates on end and the plates are placed in the racks at one end of the heating chamber and are carried by the conveyor to the opposite end where they are removed. In prior art structures, the chamber is heated by various methods so that when the plates emerge at the exit end of the chamber, they are in dry condition.

The object of the present invention is to provide improved means for heating the chamber andV for eiectively regulating the flow of heated air through various portions of the chamber; for governing the quantity of heated air directed into and caused to ow through various portions of the chamber; and for establishing control over the mechanism for heating the air directed into the various parts of the chamber.

By the means to be hereinafter described, a mechanism is provided which will be extremely exible for heating control and will enable maximum drying elciency to be secured.

In the accompanying drawings wherein an i1- lustrative embodiment of the invention is shown, Fig. 1 is a side elevation, with some parts diagrammatically illustrated, of a drying oven construction in accordance with the invention; Fig. 2 is a similar view with the heating units omitted and certain parts shown in section, and other parts being diagrammatically illustrated; Fig. 3 is a diagrammatic view of the oven, indicating the location of the several heating controls; Fig. 4. is a sectional view on the line 4--4 of Fig. 2, looking in the direction'of the arrows; Fig. 5 is a transverse sectional view through the oven showing a portion of the conveyor, one of the air distributing fans and one of the sliding dampers or valves for controlling the amount of air admitted to the inlet side o! the fan; Fig. 6 is a sectional view on the line 6-6 of Fig. 5, looking in the direction oi the arrows; Fig. 7 is a sectional view on the line 'I-l of Fig. 6, looking in the direction of the arrows; Fig. 8 is a face view of one of the sliding dampers or valves; Fig. 9 is a front elevation of one o! the controls for regulating a, damper located in the heated air passage oi the `oven; Fig. 10 is a sectional view through the structure shown in Fig. 9, said sectional view being taken on the line IU-IU o! Fig. 11, looking they are removedv from the conveyor.

in the direction of the arrows; Fig. l1 is a horizontal sectional view of the structure shown in Fig 9 and 10; and Fig. 12 is a sectional view through a part of the heated air passage, showing one of the dampers such as is controlled by the control mechanism shown in Figs. 9, 10 and 11, the sectional view being taken on the line I2`I2 of Fig. 11, looking ,in the direction of the arrows.

Referring to Figs. 1 to 3 inclusive, the body of the oven or heating chamber is generally indicated at I, the same consisting of a lengthy structure through which the varnished plates, supported on edge, are carried by a chain conveyor, diagrammatically indicated at 2, the plates being supported between racks 3 seen in Fig. 4. The entrance end of the oven is located at the left, as viewed in Fig. 1, the same being indicated at 4,

and the platesl carried by the conveyor are car-4 ried up under the hood 5 and along on the upper stretch of the conveyor, the chains S thereof being supported on the longitudinally extending bars l mounted on the transverse supports 9 extending across the oven. After passing through the oven, the plates emerge at the opposite end of the oven, or at the point 9 where While the plates are passed through the oven they are subjected to the action of a flow of heated air to dry them, by means to be hereafter described.

Directly after the plates enter the oven, they pass into a section thereof, indicated at I0, where they are subjected to a maximum amount of heated air. The heated air thus directed over the plates, is obtained from a double unit air heater, indicated at Il in Fig. 1 and located externally of and at one side of the oven. Such heater may be of any suitable kind, preferably but not necessarily using oil as fuel. InFig. 4, the general arrangement of the various heated air-conveying ducts leading from the heater, is shown, the air heated by the burner passing through duct I2 and through connected duct` I3 and into the heated air passage i4 within the body of the oven I, said air passage being formed within the oven and along one Wall of the same by means of the longitudinally extending vertical partition I5 which separates said air passage from the interior of the oven through which the conveyor is moved. Duct 'I0 is an exhaust duct. The duct I3 connects from the heater I I into the passage I4 in section I0 of the oven and delivers a iiow of heated air into the air passage I4, from which the heated air is forced into the oven proper, at points below the plates on the conveyor, by a series of fans I6, as seen in Figs. 4 and 5. These fans I6 are located at spaced intervals within the heating chamber section I0, each fan having its motor I1 and shaft I8 surrounded by a housing I9 mounted in the side wall 60 of the oven and extending through partition I5. i

In order to control the quantity of heated air admitted to each fan from the air passage I4, a sliding damper or valve 20 is provided adjacent to each of the fans I6. The details of construction of one of these dampers will be seen in Figs. to 8 inclusive. It will be there seen that each of said dampers consists of a plate 2I mounted for vertical sliding movement relative to the partition I5, said partition being provided with a guide-way 22 in which the plate is slidable to close or partly close the opening 23 provided in the partition I5. The plate 2| is slotted as at 24 to enable it to straddle the shaft I3 of the fan and the portion of the shaft housing I9 which surrounds the fan shaft.

When the plate 2l is raised, a greater portion of the opening 23 will be rendered effective to permit an increased amount of 'heated air to have access to the fan, and when the plate is lowered, the opening will be more or less restricted and a reduced quantity of heated air admitted. The raising and lowering of the damper plate is performed manually, and to enable this to be done, the plate is provided with a frame consisting of downwardly extending parallel guide bars 25 adapted to be clamped at any selected position against a cross bar 26 forming part of the oven supporting structure 21. The clamping means consists of thumb screw 28 and bar 29.

From the foregoing, it is obvious that by adjusting the vertical position of the damper, the amount of heated air admitted to the fan from air passage I4 can be effectively regulated, and said heated air will be directed by the fan through the angular baille 30 (Fig. 5) and thence upwardly past the plates carried by the conveyor and above the fans. In the arrangement shown, three fans are employed in the section I6 of the oven, and since the plates enter said section of the oven directly after being placed in the conveyor, it is desirable that at least the first two of the three fans shall have their dampers 20 opened to maximum raised position, the last of the three fans usually requiring its damper to be partly closed.

It will, of course, be understood that the number of fans located in section I0 of the oven and the regulation of hot air admission thereto may be altered accordingly as this is dependent upon surrounding working conditions. Extending from the top of the oven over the section I0 thereof, is a duct 62 connecting to suction fan mechanism 63 by which odors or gases may be exhausted from section I0 of the oven.

The control of the delivery of heated air into the air passage I4 of oven section I0 is additionally effected by means of a damper 3l located in the entrance duct I3, said damper being regulated by a thermostatic control 32 o f conventional construction. An additional heat control for this section of the oven comprises a thermostatic control tube 33, located in the duct I3, and which through suitable control means diagrammatically indicated at 34 in Fig. 3 regulates the operating periods of the burner.

It will thus be obvious that the ow of heated air into section I0 of the oven may be regulated in several ways, namely, by the setting of the several sliding dampers 20; by the setting of the thermostatic control 32 for the damper 3| and by the thermostatic control governed by the tube 33, acting to shut off and start up the heater I I when required.

In addition to the heating'means indicated at II, a second heater shown at 40 is employed. The same maybe a single unit type since the output thereof need not be as great as that of the heater II. Said heater 40 is employed at the position shown in Fig. l, and the heated air emerging therefrom passes through the duct 4I and enters in the air passage 42 located between the partition l5 and the side wall of the oven as described in respect to the chamber I4 but separated therefrom by the intervening vertical walls 43, 44 and 63', Fig. 2. The passage 42 is divided by a horizontally disposed partition 66. which divides said passage into upper and lower portions, the heated air from the burner 4l entering into the upper portion of the passage and passing therefrom into two separate lower portions 61 and 68 through the ducts 45, 46, the flow of heated air through each of said ducts 4l, 46 being regulated by a damper 41 (Figs. 9 and 12) pivoted in said ducts and in its closed position. adapted to seat against the gaskets 48, 49 (Fig. 12). The damper 41 is adapted to be operated by thermostatic control means indicated at 64. Since the type of thermostatic control is of known construction, the details thereof need not be herein set forth. It is sufficient to state that when the temperature of the heated air within the portion of the oven through which the conveyor is moved reaches a predetermined level, the operating link 5I of the thermostatic control means 50 will be moved inwardly to cause lever 52 to swing the damper 41 open to the required extent to permit the flow of heated air into the lower portions of the chamber 68 to reach the several fans I6a,'the iiow of air to said fans being additionally controlled by means of the slide dampers 20 adjacent to each of said fans as heretofore described. The operation of the thermostatic control means 50 for each damper 41 is governed by means of a thermotube I4 located within the portion of the oven through which the conveyor moves, as shown in Fig. 11.

Since the longitudinally and horizontally extending partition 66 is interrupted as at $5, the lower portion of the air chamber 42 is divided into two separate sections 61 and 68, the opening 45 communicating with section 68, and the opening or duct 46 establishing communication between the air passage or chamber 42 and the section 61. Since each of the openings 45 and 46 has its own damper, controlled by its own thermostatic control it will be obvious that the ow of heated air into the two lower sections 61 and 68 of the chamber 42 may be separately regulated and controlled. Since the various fans are also subject to control, it will be obvious that great flexibility of heat regulation for the entire oven may be readily had.

The desired baking temperature in the several sections of the oven is maintained by means of the several thermostatic control devices, the operation of which is controlled by suitably located control tubes. For example, control tube 33 located in duct I3 causes operation of control device 34 to shut off the heater I I when rise of temperature over a predetermined level occurs. Similarly thermotube 1I located in duct 4I controls operation of device 12 tor shutting ''il' heater 40 when necessary. Thermotube'13 located in the oven, controls operation of thermostatic device 32 which regulates the position of damper 3| (Fig. 4) to govern the iiow of heated air into air passage I4. Thermotube 53, located in the oven at substantially the points shown, govern the operation of the two control devices 50 which operate dampers 41 in the two ducts 45 and 46.

Briefly, the operation of the oven is substantially as follows:

The several controlling devices indicated at 32, 34, 50 and 12 are first adjusted for the required baking temperature. The slide dampers 20 are next adjusted. In general, it will be found that the maximum heat will be required at the entering end of the oven or in the left end of section l0. Accordingly, the slide dampers 20 for the rst two fans I6 will probably need to be fully opened. The other slide dampers may be closed to the required extent. The plates carried through the section I of the conveyor receive the maximum application of heat; the heat then being deo'a/se/d in the central part of the oven and again increas adjacent the exit end or above the section 6 thereof. Then, as the plates emerge at the exit end of the conveyor, cooling blasts are directed against them by fans 80 to enable the plates to be handled and facilitate their removal from the conveyor.

While I have shown an embodiment of the invention, it is obvious that numerous modiiications may be made without departing from the spirit of the invention. The number and location of the several control devices may be changed; the number of air-distributing fans may be increased or decreased, and numerous changes in structure are possible, as will be apparent to those skilled in this art. By the arrangement shown and described complete and flexible control of the temperature existing in the several sections of the oven is secured and numerous other advantages are obtained.

What we claim is:

1. In a structure of the character described, a drying chamber, a conveyor movable through said chamber for carrying plates to be dried, an

improved drying y air passage separated from the chamber by a partition, means for delivering a ow of heated air into the air passage, the partition having an opening establishing communication between the air passage and the chamber, a fan located within the chamber and infront of said opening and having its ingress end facing said opening, a shaft 'on which the fan is secured extending through said opening, a vertically adjustable plate constituting a damper mounted for raising or lowering movement to thereby regulate the size of the opening, said plate being provided with a vertically disposed open-bottom slot straddling the fan shaft, means carried by the plate and extending externally of the chamber for enabling the plate to be manually raised or lowered and fixed in any selected position, and means for exhausting the air from the drying chamber.

2. In a structure of the character described, a drying chamber, a conveyor movable through said chamber for carrying plates to be dried, a

vertical partition in said chamber forming an air passage therein, said partition having an opening establishing communication between the .chamber and the air passage, a fan located in the chamber in front of the opening, power means for the fan located externally of the chamber and having a shaft extending transversely through the air passage and through the opening in the partition and into the chamber, the fan being secured on said shaft, g des disposed along the sides of the opening, a te vertically adjustable in said guides and co stituting a amper to thereby regulate the effective size of eopening, said plate being shaped to extend` around the fan shaft, the chamber having an/ opening located below the vertically adjustable plate, an extension on the plate projecting downwardly through said last-mentioned opening to the outside of the chamber, and clamping means located outside of the chamber for engaging said extension and holding the same at any selected position of the plate, and means for exhausting the air from the drying chamber.

FREDERICK S. BAILEY. PAUL SCHONE. 

